Identity Unified Authentication Scheme For Blockchain Privacy Protection Based On Stealth Address

Identity authentication is the basis of establishing trust relationship between communication parties.Traditional identity authentication is mainly offline identity authentication based on credentials and central electronic identity authentication.However,offline identity authentication requires users to carry a variety of documents and show physical cards during verification,which brings great inconvenience to practical applications.In addition,there are also security concerns of privacy information disclosure and excessive access to the information when verification.The development of central electronic identity authentication technology is relatively mature.However,since users' information are stored in the central server,traditional centralized authentication greatly relies on the trust of the center,which makes it easy to encounter DDOS(Distributed Denial of Service)and other attacks.This may result in information leakage and service unavailability.This thesis improves and optimizes the Dual-Key stealth address protocol,and on this basis,a set of key derivation and update algorithms are designed to achieve the unlinkability among users' identity information to protect their privacy.Besides,considering the actual demands of user's independent management and partial presentation of identity information,this thesis uses the improved stealth address algorithm mentioned above to design and improve the blockchain-based stealth address privacy protection identity authentication scheme.Firstly,as the exchange management system of trust relationship,blockchain technology makes use of the decentralized feature,linking a variety of identity providers to authenticate and store users' identity information on the blockchain to achieve tamper-proof and publicly verifiable requirements.Secondly,aim at some specific scenarios where exist the requirement of multiple interactions authenticating identity between the same identity provider and the user,this paper takes advantage of bilinear pairing on the Elliptic Curve to reduce the number of initial key pairs from two to one to improve system compatibility.Besides,by extending the life length of shared secret between two participants can optimize dual-key stealth address protocol to improve efficiency of the algorithm.Finally,experiments are carried out based on SM9 cipher database to simulate the original scheme and the improved scheme to analyze and compare the performance of these two schemes.